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Carbon sinks will not be able to keep absorb carbon dioxide emissions at current rates, leading scientists have warned.

An international team of 30 researchers, including three Australians, reviews a large body of research on carbon sources and sinks in the journal Nature.

"Although carbon sinks have a role to play in absorbing excess carbon dioxide, it is possible that the net global terrestrial carbon sink may disappear altogether in the future," said lead author Professor David Schimel, from Germany's Max Planck Institute for Biogeochemistry.

'Carbon sink' is an expression used for the uptake of carbon dioxide by oceans and land-based plants. Terrestrial and marine environments are currently absorbing about half of the carbon dioxide that is emitted by fossil-fuel combustion.

But there is no guarantee this situation will remain steady, the scientists argue.

They believe that current uptake of atmospheric carbon dioxide by oceans and vegetation is inflated by forest regrowth and carbon dioxide 'fertilisation'  both of which are unlikely to continue.

Over the past decade, changes to land use in North America have seen young forests planted on agricultural land.

While trees are growing quickly, they absorb more carbon dioxide from the atmosphere than they release. But once these forests reach maturity, they will absorb and release roughly equal quantities.

In addition, global consumption of carbon dioxide by plants is currently high because of carbon dioxide 'fertilisation'  more carbon dioxide in the atmosphere makes plants grow more quickly.

But there are physiological limits to this effect, and when CO2 reaches saturation point, plant uptake will slow down, the scientists predict.

"Land and ocean processes have, in essence, provided a major, but far from permanent, subsidy to humans," said co-author Professor Chris Field from the Carnegie Institution of Washington.

Human activities that emit carbon dioxide include burning of fossil fuels and deforestation.

There are two main terrestrial carbon sinks, one in North America, the other in Eurasia. The Eurasian sink is twice the area of the North America sink, but they absorb similar quantities of carbon dioxide, the researchers believe.